Current optical switch technologies for high energy/high power laser beams use an electro-optical Pockels Cell based on deuterated potassium dihydrogen phosphate (DKDP) switch crystals, with electric fields applied either in a longitudinal or transverse orientation as shown in FIG. 1. The applied electric field changes the polarization of light beam, and the polarization changes can be converted to intensity modulation and redirection using external polarizers. Devices based on transverse electrode geometries have two drawbacks: they require a large switching voltage (>55 kV at a 25 cm aperture) that increases with aperture size; and the appropriate crystal orientation to achieve electro-optic switching results in an anisotropic optical refractive index in the aperture plane (birefringence), which induces undesired polarization rotation. This birefringence is typically compensated for by using a pair of two matched devices, which typically requires stringent matching of the thicknesses of both crystals to better than 1 μm.
FIG. 1 illustrates definitions for crystal, aperture, and electric field orientations. The longitudinal electric field (E-field) is parallel to the optical propagation direction z, while transverse E-field (along x) is perpendicular to the optical propagation. The optical input has a finite transverse extent in the x-y plane, described by the optical aperture. The crystal thickness is measured along the propagation direction z.
Despite the advances made in high power optical switches, there is a need in the art for improved methods and system related to optical switches.